Companion Planting: Organic Gardening Tips and Tricks for Healthier, Happier Plants

By Allison Greer and Tim Greer

A practical and beautiful guide to companion planting for organic gardening success

Companion planting techniques have been used for centuries to facilitate better, more nutritious, and more abundant crops. With Companion Planting, you’ll have all the information you need in clear, concise terms and with charts and garden plans you can copy or modify to suit your family’s needs.

Starting with the basics of organic gardening, such as how to prepare quality soil and the importance of cover crops and organic fertilizer, author Allison Greer explains the principles of companion planting, how plants interact, and how you can use that information to your garden’s benefit. Fun companion planting facts include:

• Beets will grow better if surrounded by mint or garlic
• Tomatoes should not be planted near cabbage
• Flax helps protect some root vegetables from pests
• Tomatoes will thrive when planted near carrots
• Your celery will be happier if it’s far away from corn
• Broccoli and dill make a terrific garden pair
• And much, much more!

Companion Planting is a treasure for gardeners with busy lives who want an easy reference guide for planning their ideal kitchen garden.

• Language: English
• Publisher: Skyhorse
• Release date: Mar 5, 2019
• ISBN: 9781510742604

Allison Greer

Allison and Tim Greer are avid organic gardeners and grow as much of their food as possible. Allison is the author of Homesprout, a blog dedicated to documenting her efforts in creating a “homemade” life, and a social studies teacher. Tim is a photographer, who also enjoys gardening and cooking. Their homestead is in Schuylerville, New York.

Book preview

Chapter 1

AN INTRODUCTION TO COMPANION PLANTING

On Growing Things

Despite all the practicality of modern convenience, watching something edible grow still possesses a delicate magic that can’t be replicated in the grocery store. Every time I talk to people about gardening, they either profess their love for growing things, or they see gardening as something beyond the realm of possibility. In all cases, people appear to recognize the majesty of a simple garden.

I designed this book for the kitchen gardener. A kitchen gardener is an individual who cultivates a garden to provide for his or her family and to enrich the family diet. The kitchen garden is so named because it is often situated near the house and can provide most of the family’s vegetables and fruits.

I recognize that most of you who pick up this book may also work full time. Like the typical American, you probably work at a job that demands a good portion of your waking hours. Perhaps you’ve looked to gardening for some stress relief, or to economize; maybe you’ve turned to gardening to refocus your priorities. Maybe you’ve begun to reject the industrialized food system and are hoping to produce a wholesome, organic, homegrown alternative. Whatever the reason, my goal is to shape your understanding of gardening into a fulfilling yet manageable component of your daily life—a bit of daily magic.

On Companion Planting

My definition of companion planting is very basic, and perhaps more generic than the traditional understanding.

Companion Planting—Plant many things. Mix them up—plant herbs, vegetables, and flowers together. Watch them grow.

There’s more to discuss. I still have to tell you about soil, and bugs, and chemicals (never, ever, ever). Still, the definition I’ve provided sums up my approach to gardening fairly well.

Creating an environment where flowers, edibles, and herbs all intermingle describes a version of companion planting that is approachable to newer gardeners, those who garden in tiny spaces, and those with room to spare.

If you’ve decided to grow an organic garden, companion planting offers a way for you to grow healthy and resilient plants without relying on harmful chemicals for their survival. Companion planting is ideal for kitchen gardeners, because all of your plants will be flung together in a beautiful configuration.

The companion planting techniques described in this book are based on the understanding that both above and below the surface of the soil, plants interact. It is clear that plants do not exist in nature in isolation. Every aspect of plant production is dependent on some level of cooperation with the surrounding plants, insects, and microbes in the soil.

Above the soil’s surface, it is undoubtedly observable that some flowers attract pollinators to the garden. Bee balm is a magnet for honeybees, an aromatic delight for their instinctive nectar and pollen collecting habit. While the honeybees may initially be drawn to the garden by bee balm flowers, they’ll also visit the flowering blossoms of the tomato. Flowers may initially appear superfluous to the average vegetable farmer, but the presence of flowers attracts beneficial pollinators to the garden in general.

Many plant combinations offer a multitude of benefits, and my reasoning for companion planting follows that approach. For instance, some may scoff at the garden lore that the presence of borage can improve the flavor of tomatoes. That idea is somewhat subjective and difficult to substantiate. However, borage does attract hornworms away from tomato plants. Therefore, while the first reason for interplanting borage and tomatoes cannot be substantiated with evidence, the latter can. If borage can deter hornworms and also improve the flavor of tomatoes, well, that’s even better. I’ll collect the hornworms to feed our chickens, and the tomatoes and borage flowers will go in my salad.

It’s also been shown and corroborated by scientific evidence that insects interact with other insects. For example, even a first year gardener has witnessed that same tomato hornworm, burdened by parasitic wasps, munching on its last tomato leaf before it succumbs to the larvae, shrivels, and dies. I sighed with dismay the first time I saw aphids on my tomatillo leaves, but two days later, the ladybugs were there to collect their lunch. In fact, it’s estimated that 95 percent of insects in the garden are beneficial, and many of them are predatory.

Plants also communicate with each other. Some of these actions are not as observable to the gardener, because they cannot be seen with the naked eye. For instance, if a tomato plant has been attacked by a pest, it secretes a chemical to warn the other tomato plants that an attack is imminent. The fragrance of the chemical secreted by the attacked plant will send a message to the other neighboring plants. Those plants will then produce chemicals that are actually toxic to the pests.

In other cases, a plant can reduce its own damage by changing the taste of its leaves. Once the leaves have been chewed, the plant will collect bitter compounds to make the leaves unappealing to pests. Beneficial insects don’t generally chew on leaves, and they won’t be deterred by the bitterness.

Scientists, and even some gardeners, often dismiss any companion planting as simple storytelling, a folktale woven by optimistic and naive gardeners. It is true that companion planting techniques are difficult to re-create in a controlled environment for specific scientific analysis. There are incalculable variables that can influence a plant’s growth. However, there have been numerous scientific studies devoted to specific plant combinations, and many of those studies have confirmed the long-held observations of companion gardeners.

While scientists have not been able to test every specific plant combination (even the possibilities are intimidating), it is clear that plants benefit from the companionship of other plants. That’s how plants have grown since the beginning of time. Plants, insects, and microbes in nature interact—every living organism interacts—and sometimes that interaction hurts, but most of the time it helps. To ignore that collaboration in your backyard garden by planting each crop in a separate bed, in a neat little row, with large swaths of bare soil, is to ignore nature’s lesson. Forests and prairies do not have neat little rows of monocropped vegetation, or bare floors swept clean from debris. No wonder backyard gardeners are constantly battling insects that swoop in to feast on the unprotected plants. Most pests are attracted by smell and taste. When we present our little edibles exposed in the garden unprotected, it’s as though we’re serving them up on a platter.

When companion planted beds are established in a garden, the level of insect life—of both beneficials and pests—increases exponentially. Even though the number of pests you see may escalate, the damage and destruction you’ll observe will lessen greatly. Plant pests will become confused by the multitude of smells and tastes, and it will make it more challenging for them to find their favorite plant to munch. By mimicking nature through companion planting, you encourage biodiversity and create a mini ecosystem within your backyard. The opportunity for a singular pest to overtake that ecosystem is not present.

In fact, it is strange and curious that the agricultural sciences have chosen to pursue herbicides, fungicides, pesticides, chemical fertilizers, and genetic modification rather than attempt to emulate nature’s defense system. Because all of these techniques run contrary to nature, they are all doomed to eventual failure. Unfortunately, short-term economic gain often supersedes a concern for our collective environmental health.

Outside of its ability to create a healthier garden ecosystem, companion planting also offers gardeners with limited room a chance to expand the selection of edibles they can produce. Interplanting vegetables, flowers, and herbs in a single garden bed offers a plethora of benefits that reaches far beyond pest control. Reducing the available bare space around plants creates a hot and humid environment beneath the plant leaves, and the environment makes weed germination unlikely. The shelter those leaves offer forms a habitat for beneficial predators and parasites.

Varying plants by height provides shade for plants that would be too hot on their own. Lettuce will last in the garden much longer if it’s nestled in the shade of a larger leafy vegetable.

Plants also vary in their root depth. Through interplanting, a gardener could combine a plant that possesses a shallow root system with one that generates a deep root structure. The plants will be able to inhabit the same space without competing for nutrients. The varied root structure will also aerate the soil.

Science has demonstrated that legumes, like peas and beans, fix nitrogen to their roots, and that the nitrogen accumulated will aid the ravenous roots of heavy feeder crops that have been established nearby. As legumes actually add nutrients to the soil, a companion gardener might combine the legumes with an edible that depends on a high level of nutrients to thrive. With an awareness of the differing demands of varying plants, companion planting seeks to maintain a nutrient balance in the soil.

In some cases, gardeners hoping for complementary plant combinations might inadvertently design a scenario that encourages plant competition. Some plants can inhibit the growth of their neighbors. Wormwood, the plant origin of absinthe, is known to emit chemicals that kill or stunt the growth of neighboring plants. It has been well documented that black walnut trees exhibit similar properties. Juglone, the staining dye of the black walnut, has been identified as the toxic chemical. Like wormwood and black walnut trees, some plant roots will emit chemicals that reduce the productivity of particular plant neighbors. This protective nature of plants is called allelopathy. The chemical process allows plants to establish territory and stake their ground before a competitor moves in. Sometimes a plant will emit an allelopathic chemical while it is living, and others will as they decompose.

Beyond all the other reasons provided for companion planting, it must be understood that a companion planted garden is quite beautiful. Single file plants are neat and organized, but they’re a bit boring. The haphazard nature of a companion planted kitchen garden is much more romantic in its design.

To devise a companion planted garden that meets your needs, start with the plant combinations I’ve suggested. The bed designs I’ve drawn are based on scientific studies, and the steady observations of gardeners over many generations, including my own. They can be scaled smaller or larger, depending upon the space you have available. It is my sincere hope that even those of you who claim only a tiny patch of earth will still find this book useful. If you have only a sunlit balcony, or a tiny strip of space between the porch and the sidewalk, you can still grow something. Throughout these pages, I offer options for those of you limited by space.

Companion planting does necessitate more planning and forethought than a traditional garden, but by emulating nature, and designing a micro ecosystem for the kitchen garden in the backyard, you will find your garden much less troubled by diseases and pests, and you will spend most of your time in the garden harvesting, transplanting, and seeding new crops.

Chapter 2

THE PRINCIPLES OF COMPANION PLANTING

The central understanding at the heart of companion planting is that an organic garden can thrive and flourish when nature is emulated, and interaction is encouraged and supported—not ignored or suppressed.

Kale with coneflowers

A successfully planted organic garden won’t have the same appearance as a conventional garden. A chemically dependent garden can be planted in tidy rows because the chemicals will keep pests and diseases somewhat in check. However, the apparent sterility and organization of a chemically dependent garden is deceiving.

At first glance, my companion planted beds might seem a bit random in their organization. There aren’t many neat rows, bare soil, or hard edges. However, my beds are organized—they’re organized conceptually by the following five fundamental principles.

Principle 1: Crop Rotation

Switching the crops grown in your beds every year will disorient soil-dwelling pests and reduce the impact of any diseases that have lain in wait for an edible’s return. Tomatoes are notoriously susceptible to a wide assortment of diseases, including fusarium wilt, verticillium wilt, and bacterial wilt. Those diseases can overwinter in the earth, and they will feast on your tomato plants each year, as long as they can find them in the soil. However, if the tomatoes migrate from bed to bed like transient gypsies, the diseases will languish, and the pests will starve and die off. When planning your garden, try to rotate crop families so that a repeat family is planted in the same bed only every four years. This can be frustratingly difficult if you have a small space. The garden space, however small, should be divided into at least 4 or 6 sections so that efficient crop rotation is possible.

Green tomatoes and borage

Rosemary with petunias

Crop rotation also encourages a balanced level of nutrients in each bed. If the same crops, or crops from the same family, are planted in a bed year after year, the produce harvested will diminish in size, quality, and productivity. While some crops, like cabbage or corn, heavily feed from plant beds, others, like peas or beans, replenish the soil. By rotating the crops each year, nutrients will rebuild, and soil will sustain a reasonable level of nutrient density. With that in mind, try not to repetitively plant heavy feeders in the same bed season after season.

The root depth of various crops differs drastically. Radishes and spinach have relatively shallow roots (around 12 inches). By comparison, the roots of a squash plant can dig down as far as 6 feet. Deep taproots pull buried nutrients up from the soil. They will travel much deeper than any double-digger, and they won’t require a shovel. They exemplify how your plants can work the soil for you without you ever having to deeply till.

Through crop rotation, plant beds have access to all kinds of root depth, and the deeper taproots will aerate the soil on a rotating basis. If plants with different root depths are paired with each other, they won’t compete for the same nutrients, and their varied rooting patterns will utilize the space more resourcefully. If crop roots aren’t in competition, the plants can also be seeded more intensively.

Principle 2: Interplant

Let’s be clear. When I use the term interplant, I’m not referring to a bed of cabbage with a few marigolds decoratively arranged at either end. When I interplant, each bed generally contains between five and seven crops, flowers, or herbs, and by strategically considering their varied rooting depths, final height, growth rate, and shade tolerance, they’ve been arranged to symbiotically contribute to each other’s success. (The updated term for this type of gardening is called polyculture, but let’s not get caught up in semantics.)

Many new companion gardeners are concerned about the space occupied by nasturtiums, zinnias, calendula, and other flowers, and note that the flowers decrease the space available for vegetables. Ultimately, in my experience with companion planting, I’ve found that an interplanted bed is often capable of producing a higher output of produce, even though flowers and herbs take up some of this space. Pests are distracted by the flowers and herbs, or eaten by beneficial insects. The edibles are left to thrive and grow much healthier and more robust than they would have otherwise.

Grasshopper on a sunflower

I’ve included designs for a plethora of interplanting within the specific plant chapters of this book. However, if you’ve moved beyond the beginner level, and would like to try your hand at designing your own companion planted bed, make sure to take the following interplanting requirements into consideration. All of the following should be compatible in order for a companion planted bed to work as intended.

Growth Rate—I once made the mistake of seeding squash and nasturtiums in a